The ornamental design for a samplestoragetube, as shown and described.
FIG. 1 is a perspective view of a sample storage tube.
FIG. 2 is a front view of the sample storage tube depicted in FIG. 1, with the rear view being identical.
FIG. 3 is a left side view of the sample storage tube depicted in FIG. 1, with the right side view being identical; and,
FIG. 4 is a bottom view of the sample storage tube depicted in FIG. 1, with the top view not showing any claimed subject matter and therefore being omitted.
The broken lines in the drawings depict portions of the sample storage tube that form no part of the claimed design.